1. Technical Field
The present invention relates to an image display system, and in particular relates to an image display system having an organic electroluminescent device.
2. Description of the Related Art
Recently, with the development and wide application of electronic products, such as mobile phones, and notebook computers, there have been increasing demands for flat display elements which consume less power and occupy less space. Organic electroluminescent diodes are popular for use in flat panel displays as they are self-emitting and highly luminous, provide wide viewing angles, have a fast response speed, and a simple fabrication process.
An organic electroluminescent diode is an LED that uses an organic layer as the active layer. In recent years, organic electroluminescent diodes have been gradually applied in flat panel displays. One trend in organic electroluminescent diode technology is to achieve high luminescent efficiency and long operating lifetimes.
Several methods have been employed to achieve full color emission in organic electroluminescent devices. In general, there is a major tendency to fabricate full color organic electroluminescent devices by a method of RGB emitting layers or a color changing method. Among these methods, the so-called “color changing method” indicates that white organic electroluminescent diodes are formed respectively on corresponding red, green and blue color filters, and then driven by bias voltages to emit red, green and blue respectively.
In the direct full-color display technique, there is a tendency to fabricate full color organic electroluminescent devices by a method of RGB emitting layers. The so-called method of RGB emitting layers indicates that red, green and blue color arrays are formed, and then driven by bias voltages to emit red, green and blue, respectively. The individual aging rates of RGB organic electroluminescent materials, however, are different and lead to color deterioration of the organic electroluminescent device after a period of time.
Accordingly, a full-color organic electroluminescent device with a color filter has been developed to solve the problems caused by the above full-color organic electroluminescent devices. In particular, white light emitted from a white organic light emitting diode is converted to RGB by passing through the RGB color filters. Nevertheless, since the RGB emission spectrum of the white organic electroluminescent device does not precisely correspond to the RGB transmission spectrum of RGB color filters, the spectral FWHM (full width at half maximum) of the filtered RGB luminescence is enlarged and reduced, such that color saturation (NTSC ratio) of the full-color display employing the white organic electroluminescent device and RGB color filters is reduced, limiting the color range thereof.
Therefore, it is necessary to develop a simple and efficient manufacturing method and structure for a full-color organic electroluminescent device.